Expandable spinal prosthesis

ABSTRACT

A device for insertion between spinous processes of adjacent vertebrae is provided and may include a rod having a first threaded portion and a second threaded portion. The first threaded portion may be coupled to the second threaded portion at a joint. A plurality of members may be movable between a compressed condition and an extended condition when the rod is rotated relative to the plurality of members. The first threaded portion and the second threaded portion may be uncoupled at the joint after the plurality of members are moved from the extended condition to the compressed condition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 12/294,357 filed on Dec. 29, 2009, which is a 371 U.S. National Stage of International Application No. PCT/US2007/007206, filed Mar. 23, 2007, which claims the benefit of Foreign Patent Application No. GB 0605960.4, filed Mar. 24, 2006. The disclosures of the above applications are expressly incorporated herein by reference.

FIELD

The present disclosure relates to the insertion of one or more spacing means in the human vertebral column and is a further improved means of provision and insertion of such spacing means.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

In another application by the same inventors (0502872.5), an improved means of achieving the desired separation of adjacent vertebral processes is provided in the form of a tapered segmented screw-like device which can be deployed using minimally invasive surgical techniques known to those skilled in the surgical art. It is the object of the present invention to provide a further improved means of separating the adjacent vertebral processes which has a minimal cross-sectional profile during insertion so that both the time taken for the surgical procedure, and the trauma caused by the procedure, are further reduced. In addition, the manufacture of the present invention is less complex and therefore less costly than that of the device described in the above mentioned previous application.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

The present invention consists of a plurality of shaped members which are pivotally joined to each other and arranged around a central screwed rod which is supported by a collar at one end and a threaded collar at the opposite end, said collar and collar being located within the pivoting axis of the adjacent members forming each end of the device.

In one configuration, a device for insertion between spinous processes of adjacent vertebrae is provided and may include a rod having a first threaded portion and a second threaded portion. The first threaded portion may be coupled to the second threaded portion at a joint. A plurality of members may be movable between a compressed condition and an extended condition when the rod is rotated relative to the plurality of members. The first threaded portion and the second threaded portion may be uncoupled at the joint after the plurality of members are moved from the extended condition to the compressed condition.

In another configuration, a device for insertion between spinous processes of adjacent vertebrae is provided and may include a rod having a first threaded portion and a second threaded portion. The first threaded portion may be coupled to the second threaded portion at a joint. A plurality of members may be movable between a compressed condition and an extended condition when the rod is rotated relative to the plurality of members. A collar may be threadably attached to the rod and may move along the rod when the plurality of members are moved from the extended condition to the compressed condition. The collar may be threadably attached to one of the first threaded portion and the second threaded portion when the plurality of members are in the extended condition and may be threadably attached to the other of the first threaded portion and the second threaded portion when the plurality of members are in the compressed condition.

In another configuration, a device for insertion between spinous processes of adjacent vertebrae is provided and may include a rod having a first threaded portion and a second threaded portion. The first threaded portion may be coupled to the second threaded portion at a joint. A plurality of members may be movable between a compressed condition and an extended condition when the rod is rotated relative to the plurality of members. A collar may be threadably attached to the rod and may move along the rod when the plurality of members are moved from the extended condition to the compressed condition. The joint may be disposed on one side of the collar when the plurality of members are in the extended condition and may be disposed on the other side of the collar when the plurality of members are in the compressed condition.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 a represents a longitudinal cross sectional schematic view of a device in accordance with the principles of the present disclosure in a pre-insertion or extended condition;

FIG. 1 b represents a longitudinal cross sectional schematic view of the device of FIG. 1 a in a compressed condition following insertion between adjacent spinous processes of adjacent vertebrae;

FIG. 1 c shows a detail of a junction of the device of FIG. 1 a in a central screwed rod;

FIG. 2 represents an orthogonal view of a junction between two adjacent members such as occurs at points B, C, D, E, G, H, I and J shown in FIG. 1 b;

FIG. 3 a shows a collar and spring of the device of FIG. 1 a; and

FIG. 3 b shows positioning of a threaded collar and spring of the device of FIG. 1 a within members of the device at a right-hand end of the device (point F on FIG. 1 b).

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference to the accompanying drawings.

An embodiment of the device is now described with reference to FIGS. 1 a, 1 b, 1 c, 2, 3 a and 3 b attached. FIG. 1 a represents a longitudinal cross sectional schematic view of the device in its pre-insertion or extended condition and FIG. 1 b represents the same view in the compressed condition following insertion between the adjacent spinous processes of adjacent vertebrae. FIG. 1 c shows a detail of the junction (23) in the central screwed rod (15) shown in FIGS. 1 a and 1 b. FIG. 2 represents an orthogonal view of a junction between two adjacent members such as occurs at points B, C, D, E, G, H, I and J shown on FIG. 1 b. FIG. 3 a shows the manner in which, the collar (11) and spring (18) referred to in the description are positioned between the members at the left hand end of the device (point A on FIG. 1 b) while FIG. 3 b shows the positioning of the threaded collar (14) and spring (18) within the members at the right hand end of the device (point F on FIG. 1 b).

The ten members of the device shown as items 1-10 in FIG. 1 a are pivotally joined at locations A to J in FIG. 1 b providing for an increase or decrease in the angle contained between adjacent members as may be required for the proper functioning of the device. As will be apparent from inspection of FIGS. 2, 3 a and 3 b, the cross sectional dimensions of alternate adjacent members differ so that at each junction between said adjacent members one member may fit inside the other member. The pivotal means provided at point A in FIG. 1 b is shown in more detail in FIG. 3A and consists of a circular collar 11 provided at diametrically opposite sides with short rod like projections 12 which together provide a pivoting axle which passes though a small aperture 13 in either side of each of the two members located around said point A. The pivotal means provided at point F of FIG. 1 b is shown in more detail; in FIG. 3B. Said pivotal means is similar to that provided at point A with the exception that said collar is replaced by a threaded collar 14 through which a centrally located screwed rod shown at 15 on FIGS. 1 a and 1 b may be advanced or withdrawn. The pivotal means provided at all other junctions between adjacent members is shown in FIG. 2 and comprises a cylindrical axle-pin 16 provided with concentric sections of different diameters to facilitate its retention within the small holes 17 provided in the respective adjacent members. A wire spring 18 is provided at each pivotal joint between said adjacent members so as to tension said members into an appropriate position during compression and extension of the device of the invention in the manner described herein.

The screwed rod 15 in FIGS. 1 a and 1 b is provided at its left hand end with an unthreaded portion 19 to facilitate its rotating motion in the collar (11 in FIG. 3 a) and a terminating cap 20 to prevent its complete withdrawal through said collar. Said screwed rod is further provided with a stop nut 21 in FIGS. 1 a and 1 b which is fixed at a permanent location on screwed rod 15 by means of a transfixing pin (22 in FIG. 1 a) or other suitable means.

Said screwed rod is provided at point 23, shown to the right of stop nut 21 in FIG. 1 b, with a joint (shown in further detail in FIG. 1 c) which facilitates removal of the section of said screwed rod to the right of said joint. Detachment of one portion of said screwed rod from the other portion may be advantageously provided by means of a threaded portion of reduced diameter on one section of said screwed rod shown in FIG. 1 c at 23 a which enters a matching socket 23 b on the other section. Said screwed rod is further provided at the right hand end with a shaped portion 24 for attachment of a driving tool which may be in the form of a catheter as shown at 25 on FIGS. 1 a and 1 b.

In operation said driving tool is attached to said shaped portion (24) of said screwed rod (15) which is rotated so as to render the device into its expanded or stretched condition as shown in FIG. 1 a. The device with driving tool attached is now advanced down a previously inserted canula into the body of the patient and positioned between the spinous processes which require separation. The driving tool is then used to rotate said screwed rod in an anti-clockwise direction thereby compressing the device of the invention into the condition shown in FIG. 1 b. At this point the stop nut 21 engages with the threaded collar 14 to prevent further rotation of said screwed rod and to facilitate the detachment of the section of said screwed rod to the right of joint 23 by continued rotation of said driving tool. Said driving tool may now be withdrawn from the body of the patient leaving the device of the invention located as desired in its compressed condition and between the spinous processes of the adjacent vertebrae.

The device and the components thereof may be manufactured from any materials which have been shown to be suitable for implantation in the human body. Such materials may if desired be coated or otherwise treated to reduce inflammation and or promote healing of insertion wounds using materials and methods known to those skilled in the art of production of medical prostheses. If the device is manufactured wholly from non-metallic components radio opaque materials may be advantageously incorporated in some or all of the components in order to render the device or parts thereof visible under fluoroscopy during the procedure for implantation in the human body.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

1. A device for insertion between spinous processes of adjacent vertebrae comprising: a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint; and a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members, said first threaded portion and said second threaded portion being uncoupled at said joint after said plurality of members are moved from said extended condition to said compressed condition.
 2. The device of claim 1, further comprising a first collar rotatably supporting said rod at one of said first threaded portion and said second threaded portion.
 3. The device of claim 2, further comprising a second collar threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition.
 4. The device of claim 3, wherein said rod is rotated relative to said second collar when said plurality of members are moved from said extended condition to said compressed condition.
 5. The device of claim 3, wherein said second collar is threadably attached to said first threaded portion when said plurality of members are in said compressed condition.
 6. The device of claim 3, wherein rotation of said rod causes said second collar to cross said joint and move from said second threaded portion to said first threaded portion during movement of said plurality of members from said extended condition to said compressed condition.
 7. The device of claim 1, wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition.
 8. The device of claim 7, wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition.
 9. The device of claim 1, further comprising a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition.
 10. The device of claim 9, wherein said collar is threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and said collar is threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition.
 11. The device of claim 9, wherein said joint is disposed on one side of said collar when said plurality of members are in said extended condition and is disposed on the other side of said collar when said plurality of members are in said compressed condition.
 12. A device for insertion between spinous processes of adjacent vertebrae comprising: a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint; a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members; and a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition, said collar being threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and being threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition.
 13. The device of claim 12, wherein rotation of said rod causes said collar to cross said joint and move from said one of said first threaded portion and second threaded portion to said other of said first threaded portion and said second threaded portion during movement of said plurality of members from said extended condition to said compressed condition.
 14. The device of claim 12, wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition.
 15. The device of claim 14, wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition.
 16. The device of claim 12, wherein said joint is disposed on one side of said collar when said plurality of members are in said extended condition and is disposed on the other side of said collar when said plurality of members are in said compressed condition.
 17. A device for insertion between spinous processes of adjacent vertebrae comprising: a rod having a first threaded portion and a second threaded portion, said first threaded portion coupled to said second threaded portion at a joint; a plurality of members movable between a compressed condition and an extended condition when said rod is rotated relative to said plurality of members; and a collar threadably attached to said rod and operable to move along said rod when said plurality of members are moved from said extended condition to said compressed condition, said joint being disposed on one side of said collar when said plurality of members are in said extended condition and being disposed on the other side of said collar when said plurality of members are in said compressed condition.
 18. The device of claim 17, wherein rotation of said rod causes said collar to cross said joint and move from said second threaded portion to said first threaded portion during movement of said plurality of members from said extended condition to said compressed condition.
 19. The device of claim 17, wherein said joint is disposed between two of said plurality of members when said plurality of members are in said extended condition.
 20. The device of claim 19, wherein said joint is disposed externally from said plurality of members when said plurality of members are in said compressed condition.
 21. The device of claim 17, wherein said collar is threadably attached to one of said first threaded portion and said second threaded portion when said plurality of members are in said extended condition and said collar is threadably attached to the other of said first threaded portion and said second threaded portion when said plurality of members are in said compressed condition. 